45 lines
1.1 KiB
C#
45 lines
1.1 KiB
C#
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// Copyright (c) Microsoft Open Technologies, Inc. All rights reserved. See License.txt in the project root for license information.
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#if NO_HASHSET
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using System;
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using System.Collections.Generic;
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namespace System.Reactive
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{
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class HashSet<T>
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{
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private readonly Dictionary<T, object> _set;
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private bool _hasNull;
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public HashSet(IEqualityComparer<T> comparer)
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{
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_set = new Dictionary<T, object>(comparer);
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_hasNull = false;
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}
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public bool Add(T value)
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{
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//
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// Note: The box instruction in the IL will be erased by the JIT in case T is
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// a value type. See GroupBy for more information.
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//
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if (value == null)
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{
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if (_hasNull)
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return false;
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_hasNull = true;
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return true;
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}
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else
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{
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if (_set.ContainsKey(value))
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return false;
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_set[value] = null;
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return true;
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}
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}
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}
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}
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#endif
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